gems, color theory, color, color science

Chevreul presents a practical application of his theories of color and simultaneous contrast to the industrial and decorative arts, using chromatic circles to demonstrate the relationships between hues, their mixtures, harmonies, and contrasts. Building upon his earlier researches on color perception, he shows how colors may be systematically arranged and compared and how their appearance changes according to adjacent colors and differences in tone and saturation. The accompanying colored plates provide a visual system for selecting and coordinating colors in textiles, painting, decoration, and other manufactured objects. Although not specifically concerned with gemstones, the work is relevant to gemology through its systematic treatment of color description, comparison, and perception—particularly the influence of surrounding colors on apparent hue—and forms part of the nineteenth-century development of scientific approaches to color that would later become fundamental to gemstone description and grading.